Hierarchical Variable Selection in Polynomial Regression Models

Significance tests on coefficients of lower-order terms in polynomial regression models are affected by linear transformations. For this reason, a polynomial regression model that excludes hierarchically inferior predictors (i.e., lower-order terms) is considered to be not well formulated. Existing variable-selection algorithms do not take into account the hierarchy of predictors and often select as “best” a model that is not hierarchically well formulated. This article proposes a theory of the hierarchical ordering of the predictors of an arbitrary polynomial regression model in m variables, where m is any arbitrary positive integer. Ways of modifying existing algorithms to restrict their search to well-formulated models are suggested. An algorithm that generates all possible well-formulated models is presented.     

Developing a Personal Program for Continuing Education

Abstract

The increasing number of field expeditions studying or working abroad each year is currently unparalleled by medical research efforts or data from which health professionals can make meaningful recommendations about how to keep personnel in the field healthy. The medical planning, organizing, and data are presented from a geology expedition to Guatemala involving 25 persons. Only minor medical problems were encountered, and less than 1% of the total person days at risk were lost due to illness. Eight guidelines are presented as a tool to assist any health professional in the planning and preparing of a team for the field.     

Discount-neutral utility models for denumerable time streams

This paper formulates and axiomatizes utility models for denumerable time streams that make no commitment in regard to discounting future outcomes. The models address decision under certainty and decision under risk. Independence assumptions in both contexts lead to additive or multiplicative utilities over time periods that allow unambiguous comparisons of the relative importance of different periods. The models accommodate all patterns of future valuation. This discount-neutral feature is attained by restricting preference comparisons to outcome streams or probability distributions on outcome streams that differ in at most a finite number of periods.     

试论闲暇偏好的效用和对收入分配的影响

提出了闲暇剩余这一概念,并计算了劳动者闲暇偏好对闲暇剩余的影响,同时分析了劳动者闲暇偏好对收入分配不均等性的影响.针对不同群体适当引导对闲暇的偏好,可以满足不同群体的需要,缩小收入差距的不均等性.这对解决我国当前劳动力供需紧张、人们收入差距逐渐拉大具有较强的现实指导意义.     

行为经济学与主流经济学:两个基本概念辨析

行为经济学自诞生起就与主流经济学存在分歧。其理论争论的焦点在主流经济学的两个基本立论点上,即概率判断与偏好。行为经济学基于心理学的观点对主流经济学的这两个基本概念进行了诸多方面的修正和扬弃,成为区别于主流经济学的重要标志。因此,对这两个基本概念的辨析是明晰行为经济学与主流经济学的基础内容。     

Shortage of girls in China today

China has the most severe shortage of girls compared to boys of any country in the world today, as documented by China's surveys and censuses up to 2000. This article evaluates data on sex ratios in China since before the founding of the People's Republic, and shows that the relative dearth of girls has become more extreme during the last two decades, and that the problem is real and not merely due to undercounting of girls. Daughters are lost primarily through sex-selective abortion, secondly through excess female infant mortality, and thirdly through neglect or mistreatment of girls up to age three, in cities as well as rural areas. Until recently, the dearth of girls was confined to second or higher-order births, but now couples in some provinces are using sex-selective abortions for first births. Maps show the geographical concentration of life-threatening discrimination against girls and its spread over time. Son preference, low fertility and technology combine to cause the loss of daughters in China today and compulsory family planning and the one-child policy exacerbate the problem. The discussion includes what the People's Republic of China has done to ameliorate life-threatening discrimination against girls and what further steps might be taken to improve the situation.     

模糊满意关系上的决策

在许多决策问题中,备选方案上的二元优先关系是模糊的。本文分析了基于二元模糊优先关系上的奥尔洛夫斯基(Orlovsky)算法。该算法中,具有最大的不劣于程度的元是最佳元,因此算法存在一些缺陷。本文提出了一种新算法。新算法中,具有最大满意程度的元是最佳元。新算法弥补了 Orlovsky 算法的缺陷。     

区域差异、融资偏好与企业环境依存度

随着经济增长点的多元化以及产业结构的日趋合理,我国企业发展在实现产出增长的同时也带来了严重的环境问题。以企业融资结构与企业环境依存度为切入点,运用Brander和Lewis的寡头垄断博弈分析框架,可以揭示经济增长的区域差异、融资偏好、污染税制度以及企业最优污染治理水平等变量之间的相互关系。通过对不同污染收费制度下的企业行为的比较分析,可以证明在不同的收费制度下,企业自利行为所导致的企业融资偏好以及对环境的污染程度会有所不同。     

论新制独立学院产生的制度环境

根据新制度经济学的诱致性制度变迁理论，高等教育需求持续旺盛，教育收费管制放松，进入高等教育市场存在政策壁垒、规模经济壁垒和技术壁垒，公众对高等教育的偏好以及高等学校自主权不断扩大等众多因素相互作用，构成了新制独立学院得以在20世纪90年代中后期产生的重要制度环境。     

Kurtosis and spread

An increase in kurtosis is achieved through the location- and scale-free movement of probability mass from the “shoulders” of a distribution into its centre and tails. We introduce a coherent structure of ordering and measures, requiring no symmetry assumption, that represent different formalizations of this movement. For this purpose spread functions and spread-spread plots are defined. The orderings impose growth patterns on the spread-spread plot of the distributions involved, and the weakest involve both a specific scale-matching technique and placement of “shoulders”. The role of existing kurtosis orderings and measures in this general context is identified and examples discussed throughout.